“What’s ‘ridiculous and sad’ is that President Obama does not take Iran’s repeated threats seriously,” Mr. Huckabee said in a statement. “For decades, Iranian leaders have pledged to ‘destroy,’ ‘annihilate,’ and ‘wipe Israel off the map’ with a ‘big Holocaust.’ ‘Never again’ will be the policy of my administration and I will stand with our ally Israel to prevent the terrorists in Tehran from achieving their own stated goal of another Holocaust.”

Over the weekend, Mr. Huckabee had said in an interview with Breitbart the deal brokered by Mr. Obama and other nations with Iran on Tehran’s nuclear program would “take the Israelis and basically march them to the door of the oven,” an invocation of Nazi imagery that immediately drew swift condemnation from Democrats.

At a news conference in Ethiopia Monday, Mr. Obama said such criticism from Republicans “would be considered ridiculous if it weren’t so sad.”

“Maybe this is just an effort to push [Donald] Trump out of the headlines,” Mr. Obama said. “But it is not the kind of leadership that is needed in America right now.”